1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Authenc: Simple AEAD wrapper for IPsec
4 *
5 * Copyright (c) 2007-2015 Herbert Xu <herbert@gondor.apana.org.au>
6 */
7
8 #include <crypto/internal/aead.h>
9 #include <crypto/internal/hash.h>
10 #include <crypto/internal/skcipher.h>
11 #include <crypto/authenc.h>
12 #include <crypto/null.h>
13 #include <crypto/scatterwalk.h>
14 #include <linux/err.h>
15 #include <linux/init.h>
16 #include <linux/kernel.h>
17 #include <linux/module.h>
18 #include <linux/rtnetlink.h>
19 #include <linux/slab.h>
20 #include <linux/spinlock.h>
21
22 struct authenc_instance_ctx {
23 struct crypto_ahash_spawn auth;
24 struct crypto_skcipher_spawn enc;
25 unsigned int reqoff;
26 };
27
28 struct crypto_authenc_ctx {
29 struct crypto_ahash *auth;
30 struct crypto_skcipher *enc;
31 struct crypto_sync_skcipher *null;
32 };
33
34 struct authenc_request_ctx {
35 struct scatterlist src[2];
36 struct scatterlist dst[2];
37 char tail[];
38 };
39
40 static void authenc_request_complete(struct aead_request *req, int err)
41 {
42 if (err != -EINPROGRESS)
43 aead_request_complete(req, err);
44 }
45
46 int crypto_authenc_extractkeys(struct crypto_authenc_keys *keys, const u8 *key,
47 unsigned int keylen)
48 {
49 struct rtattr *rta = (struct rtattr *)key;
50 struct crypto_authenc_key_param *param;
51
52 if (!RTA_OK(rta, keylen))
53 return -EINVAL;
54 if (rta->rta_type != CRYPTO_AUTHENC_KEYA_PARAM)
55 return -EINVAL;
56
57 /*
58 * RTA_OK() didn't align the rtattr's payload when validating that it
59 * fits in the buffer. Yet, the keys should start on the next 4-byte
60 * aligned boundary. To avoid confusion, require that the rtattr
61 * payload be exactly the param struct, which has a 4-byte aligned size.
62 */
63 if (RTA_PAYLOAD(rta) != sizeof(*param))
64 return -EINVAL;
65 BUILD_BUG_ON(sizeof(*param) % RTA_ALIGNTO);
66
67 param = RTA_DATA(rta);
68 keys->enckeylen = be32_to_cpu(param->enckeylen);
69
70 key += rta->rta_len;
71 keylen -= rta->rta_len;
72
73 if (keylen < keys->enckeylen)
74 return -EINVAL;
75
76 keys->authkeylen = keylen - keys->enckeylen;
77 keys->authkey = key;
78 keys->enckey = key + keys->authkeylen;
79
80 return 0;
81 }
82 EXPORT_SYMBOL_GPL(crypto_authenc_extractkeys);
83
84 static int crypto_authenc_setkey(struct crypto_aead *authenc, const u8 *key,
85 unsigned int keylen)
86 {
87 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
88 struct crypto_ahash *auth = ctx->auth;
89 struct crypto_skcipher *enc = ctx->enc;
90 struct crypto_authenc_keys keys;
91 int err = -EINVAL;
92
93 if (crypto_authenc_extractkeys(&keys, key, keylen) != 0)
94 goto out;
95
96 crypto_ahash_clear_flags(auth, CRYPTO_TFM_REQ_MASK);
97 crypto_ahash_set_flags(auth, crypto_aead_get_flags(authenc) &
98 CRYPTO_TFM_REQ_MASK);
99 err = crypto_ahash_setkey(auth, keys.authkey, keys.authkeylen);
100 if (err)
101 goto out;
102
103 crypto_skcipher_clear_flags(enc, CRYPTO_TFM_REQ_MASK);
104 crypto_skcipher_set_flags(enc, crypto_aead_get_flags(authenc) &
105 CRYPTO_TFM_REQ_MASK);
106 err = crypto_skcipher_setkey(enc, keys.enckey, keys.enckeylen);
107 out:
108 memzero_explicit(&keys, sizeof(keys));
109 return err;
110 }
111
112 static void authenc_geniv_ahash_done(void *data, int err)
113 {
114 struct aead_request *req = data;
115 struct crypto_aead *authenc = crypto_aead_reqtfm(req);
116 struct aead_instance *inst = aead_alg_instance(authenc);
117 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst);
118 struct authenc_request_ctx *areq_ctx = aead_request_ctx(req);
119 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff);
120
121 if (err)
122 goto out;
123
124 scatterwalk_map_and_copy(ahreq->result, req->dst,
125 req->assoclen + req->cryptlen,
126 crypto_aead_authsize(authenc), 1);
127
128 out:
129 aead_request_complete(req, err);
130 }
131
132 static int crypto_authenc_genicv(struct aead_request *req, unsigned int flags)
133 {
134 struct crypto_aead *authenc = crypto_aead_reqtfm(req);
135 struct aead_instance *inst = aead_alg_instance(authenc);
136 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
137 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst);
138 struct crypto_ahash *auth = ctx->auth;
139 struct authenc_request_ctx *areq_ctx = aead_request_ctx(req);
140 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff);
141 u8 *hash = areq_ctx->tail;
142 int err;
143
144 ahash_request_set_tfm(ahreq, auth);
145 ahash_request_set_crypt(ahreq, req->dst, hash,
146 req->assoclen + req->cryptlen);
147 ahash_request_set_callback(ahreq, flags,
148 authenc_geniv_ahash_done, req);
149
150 err = crypto_ahash_digest(ahreq);
151 if (err)
152 return err;
153
154 scatterwalk_map_and_copy(hash, req->dst, req->assoclen + req->cryptlen,
155 crypto_aead_authsize(authenc), 1);
156
157 return 0;
158 }
159
160 static void crypto_authenc_encrypt_done(void *data, int err)
161 {
162 struct aead_request *areq = data;
163
164 if (err)
165 goto out;
166
167 err = crypto_authenc_genicv(areq, 0);
168
169 out:
170 authenc_request_complete(areq, err);
171 }
172
173 static int crypto_authenc_copy_assoc(struct aead_request *req)
174 {
175 struct crypto_aead *authenc = crypto_aead_reqtfm(req);
176 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
177 SYNC_SKCIPHER_REQUEST_ON_STACK(skreq, ctx->null);
178
179 skcipher_request_set_sync_tfm(skreq, ctx->null);
180 skcipher_request_set_callback(skreq, aead_request_flags(req),
181 NULL, NULL);
182 skcipher_request_set_crypt(skreq, req->src, req->dst, req->assoclen,
183 NULL);
184
185 return crypto_skcipher_encrypt(skreq);
186 }
187
188 static int crypto_authenc_encrypt(struct aead_request *req)
189 {
190 struct crypto_aead *authenc = crypto_aead_reqtfm(req);
191 struct aead_instance *inst = aead_alg_instance(authenc);
192 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
193 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst);
194 struct authenc_request_ctx *areq_ctx = aead_request_ctx(req);
195 struct crypto_skcipher *enc = ctx->enc;
196 unsigned int cryptlen = req->cryptlen;
197 struct skcipher_request *skreq = (void *)(areq_ctx->tail +
198 ictx->reqoff);
199 struct scatterlist *src, *dst;
200 int err;
201
202 src = scatterwalk_ffwd(areq_ctx->src, req->src, req->assoclen);
203 dst = src;
204
205 if (req->src != req->dst) {
206 err = crypto_authenc_copy_assoc(req);
207 if (err)
208 return err;
209
210 dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, req->assoclen);
211 }
212
213 skcipher_request_set_tfm(skreq, enc);
214 skcipher_request_set_callback(skreq, aead_request_flags(req),
215 crypto_authenc_encrypt_done, req);
216 skcipher_request_set_crypt(skreq, src, dst, cryptlen, req->iv);
217
218 err = crypto_skcipher_encrypt(skreq);
219 if (err)
220 return err;
221
222 return crypto_authenc_genicv(req, aead_request_flags(req));
223 }
224
225 static int crypto_authenc_decrypt_tail(struct aead_request *req,
226 unsigned int flags)
227 {
228 struct crypto_aead *authenc = crypto_aead_reqtfm(req);
229 struct aead_instance *inst = aead_alg_instance(authenc);
230 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
231 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst);
232 struct authenc_request_ctx *areq_ctx = aead_request_ctx(req);
233 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff);
234 struct skcipher_request *skreq = (void *)(areq_ctx->tail +
235 ictx->reqoff);
236 unsigned int authsize = crypto_aead_authsize(authenc);
237 u8 *ihash = ahreq->result + authsize;
238 struct scatterlist *src, *dst;
239
240 scatterwalk_map_and_copy(ihash, req->src, ahreq->nbytes, authsize, 0);
241
242 if (crypto_memneq(ihash, ahreq->result, authsize))
243 return -EBADMSG;
244
245 src = scatterwalk_ffwd(areq_ctx->src, req->src, req->assoclen);
246 dst = src;
247
248 if (req->src != req->dst)
249 dst = scatterwalk_ffwd(areq_ctx->dst, req->dst, req->assoclen);
250
251 skcipher_request_set_tfm(skreq, ctx->enc);
252 skcipher_request_set_callback(skreq, flags,
253 req->base.complete, req->base.data);
254 skcipher_request_set_crypt(skreq, src, dst,
255 req->cryptlen - authsize, req->iv);
256
257 return crypto_skcipher_decrypt(skreq);
258 }
259
260 static void authenc_verify_ahash_done(void *data, int err)
261 {
262 struct aead_request *req = data;
263
264 if (err)
265 goto out;
266
267 err = crypto_authenc_decrypt_tail(req, 0);
268
269 out:
270 authenc_request_complete(req, err);
271 }
272
273 static int crypto_authenc_decrypt(struct aead_request *req)
274 {
275 struct crypto_aead *authenc = crypto_aead_reqtfm(req);
276 unsigned int authsize = crypto_aead_authsize(authenc);
277 struct aead_instance *inst = aead_alg_instance(authenc);
278 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
279 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst);
280 struct crypto_ahash *auth = ctx->auth;
281 struct authenc_request_ctx *areq_ctx = aead_request_ctx(req);
282 struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff);
283 u8 *hash = areq_ctx->tail;
284 int err;
285
286 ahash_request_set_tfm(ahreq, auth);
287 ahash_request_set_crypt(ahreq, req->src, hash,
288 req->assoclen + req->cryptlen - authsize);
289 ahash_request_set_callback(ahreq, aead_request_flags(req),
290 authenc_verify_ahash_done, req);
291
292 err = crypto_ahash_digest(ahreq);
293 if (err)
294 return err;
295
296 return crypto_authenc_decrypt_tail(req, aead_request_flags(req));
297 }
298
299 static int crypto_authenc_init_tfm(struct crypto_aead *tfm)
300 {
301 struct aead_instance *inst = aead_alg_instance(tfm);
302 struct authenc_instance_ctx *ictx = aead_instance_ctx(inst);
303 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm);
304 struct crypto_ahash *auth;
305 struct crypto_skcipher *enc;
306 struct crypto_sync_skcipher *null;
307 int err;
308
309 auth = crypto_spawn_ahash(&ictx->auth);
310 if (IS_ERR(auth))
311 return PTR_ERR(auth);
312
313 enc = crypto_spawn_skcipher(&ictx->enc);
314 err = PTR_ERR(enc);
315 if (IS_ERR(enc))
316 goto err_free_ahash;
317
318 null = crypto_get_default_null_skcipher();
319 err = PTR_ERR(null);
320 if (IS_ERR(null))
321 goto err_free_skcipher;
322
323 ctx->auth = auth;
324 ctx->enc = enc;
325 ctx->null = null;
326
327 crypto_aead_set_reqsize(
328 tfm,
329 sizeof(struct authenc_request_ctx) +
330 ictx->reqoff +
331 max_t(unsigned int,
332 crypto_ahash_reqsize(auth) +
333 sizeof(struct ahash_request),
334 sizeof(struct skcipher_request) +
335 crypto_skcipher_reqsize(enc)));
336
337 return 0;
338
339 err_free_skcipher:
340 crypto_free_skcipher(enc);
341 err_free_ahash:
342 crypto_free_ahash(auth);
343 return err;
344 }
345
346 static void crypto_authenc_exit_tfm(struct crypto_aead *tfm)
347 {
348 struct crypto_authenc_ctx *ctx = crypto_aead_ctx(tfm);
349
350 crypto_free_ahash(ctx->auth);
351 crypto_free_skcipher(ctx->enc);
352 crypto_put_default_null_skcipher();
353 }
354
355 static void crypto_authenc_free(struct aead_instance *inst)
356 {
357 struct authenc_instance_ctx *ctx = aead_instance_ctx(inst);
358
359 crypto_drop_skcipher(&ctx->enc);
360 crypto_drop_ahash(&ctx->auth);
361 kfree(inst);
362 }
363
364 static int crypto_authenc_create(struct crypto_template *tmpl,
365 struct rtattr **tb)
366 {
367 u32 mask;
368 struct aead_instance *inst;
369 struct authenc_instance_ctx *ctx;
370 struct skcipher_alg_common *enc;
371 struct hash_alg_common *auth;
372 struct crypto_alg *auth_base;
373 int err;
374
375 err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AEAD, &mask);
376 if (err)
377 return err;
378
379 inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL);
380 if (!inst)
381 return -ENOMEM;
382 ctx = aead_instance_ctx(inst);
383
384 err = crypto_grab_ahash(&ctx->auth, aead_crypto_instance(inst),
385 crypto_attr_alg_name(tb[1]), 0, mask);
386 if (err)
387 goto err_free_inst;
388 auth = crypto_spawn_ahash_alg(&ctx->auth);
389 auth_base = &auth->base;
390
391 err = crypto_grab_skcipher(&ctx->enc, aead_crypto_instance(inst),
392 crypto_attr_alg_name(tb[2]), 0, mask);
393 if (err)
394 goto err_free_inst;
395 enc = crypto_spawn_skcipher_alg_common(&ctx->enc);
396
397 ctx->reqoff = 2 * auth->digestsize;
398
399 err = -ENAMETOOLONG;
400 if (snprintf(inst->alg.base.cra_name, CRYPTO_MAX_ALG_NAME,
401 "authenc(%s,%s)", auth_base->cra_name,
402 enc->base.cra_name) >=
403 CRYPTO_MAX_ALG_NAME)
404 goto err_free_inst;
405
406 if (snprintf(inst->alg.base.cra_driver_name, CRYPTO_MAX_ALG_NAME,
407 "authenc(%s,%s)", auth_base->cra_driver_name,
408 enc->base.cra_driver_name) >= CRYPTO_MAX_ALG_NAME)
409 goto err_free_inst;
410
411 inst->alg.base.cra_priority = enc->base.cra_priority * 10 +
412 auth_base->cra_priority;
413 inst->alg.base.cra_blocksize = enc->base.cra_blocksize;
414 inst->alg.base.cra_alignmask = enc->base.cra_alignmask;
415 inst->alg.base.cra_ctxsize = sizeof(struct crypto_authenc_ctx);
416
417 inst->alg.ivsize = enc->ivsize;
418 inst->alg.chunksize = enc->chunksize;
419 inst->alg.maxauthsize = auth->digestsize;
420
421 inst->alg.init = crypto_authenc_init_tfm;
422 inst->alg.exit = crypto_authenc_exit_tfm;
423
424 inst->alg.setkey = crypto_authenc_setkey;
425 inst->alg.encrypt = crypto_authenc_encrypt;
426 inst->alg.decrypt = crypto_authenc_decrypt;
427
428 inst->free = crypto_authenc_free;
429
430 err = aead_register_instance(tmpl, inst);
431 if (err) {
432 err_free_inst:
433 crypto_authenc_free(inst);
434 }
435 return err;
436 }
437
438 static struct crypto_template crypto_authenc_tmpl = {
439 .name = "authenc",
440 .create = crypto_authenc_create,
441 .module = THIS_MODULE,
442 };
443
444 static int __init crypto_authenc_module_init(void)
445 {
446 return crypto_register_template(&crypto_authenc_tmpl);
447 }
448
449 static void __exit crypto_authenc_module_exit(void)
450 {
451 crypto_unregister_template(&crypto_authenc_tmpl);
452 }
453
454 subsys_initcall(crypto_authenc_module_init);
455 module_exit(crypto_authenc_module_exit);
456
457 MODULE_LICENSE("GPL");
458 MODULE_DESCRIPTION("Simple AEAD wrapper for IPsec");
459 MODULE_ALIAS_CRYPTO("authenc");
460
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